1. Field of the Invention
The present invention relates to the field of monitoring chemical reactions. More particularly, the present invention relates to a new and improved chemical reaction monitor for use in monitoring parallel chemical reactions.
The chemical reaction monitor of the present invention is particularly suited for real-time monitoring of oligonucleotide synthesis. The chemical reaction monitor of the present invention is also particularly suited for providing a quality control (QC) measure for oligonucleotide production.
2. Description of Related Art
Oligonucleotide synthesis is a cyclical process that assembles a chain of nucleotides. Nucleotides are added one by one through a cycle of chemical reactions, in which a particular molecule (e.g., a nucleotide) is added to a growing DNA molecule (e.g., a growing DNA chain), sometimes via catalysis, until the desired chain is complete. Generally, each cycle of chemical reactions includes the steps of detritylation, coupling, capping and oxidation.
During the detritylation or “deprotection” step, a dimethoxytrityl (DMT) group is removed from the last nucleotide of the growing DNA chain to allow the addition of the next nucleotide. The amount of DMT released from each cycle is monitored to insure a high coupling efficiency. The release of DMT is apparent because a bright orange color is emitted as DMT is released.
Monitoring of the detritylation or deprotection step in known commercial synthesizers is done in the form of a spectrophotometer monitoring a cuvette through which wash waste is passed. Such monitoring is done on a discrete per sample basis in systems that process as many as 32 oligonucleotide samples simultaneously. During the detritylation step the waste is monitored for the presence and magnitude of the orange color indicating the release of DMT. As the number of simultaneous reactions increases, the ability to use known methods to monitor reaction progress becomes prohibitively inefficient.
What is needed is a chemical reaction monitor that allows parallel monitoring of chemical reactions in which each sample may be observed and monitored both discretely and as a collection. The present invention satisfies this need and provides other advantages as well.